It does sound like she's broody, but my what a long time to be broody! Our silkies are always broody, but they do have breaks in between of several days or a week.
The others are probably bullying her because she won't be up to her normal strength even though she is eating a drinking when she does go out.
Really you should try to make her life really uncomfortable for a bit to knock it out of her. We sometimes put ours in a metal animal cage, inside their normal run so the others can still see her. Just give her food and water but no goodies. If the weather is fair she could stay there overnight, but I usually put ours back in with the other girls at night then back in the cage next morning. some people say giving them a cool bath works, but I've never tried that one!
